Lens apparatus including image pick-up optical unit and controller for controlling change of aperture diameter

ABSTRACT

This invention discloses an optical apparatus including an image pickup optical unit, a light quantity adjustment unit inserted in the optical axis of the image pickup optical unit, the light quantity adjustment unit changing the aperture diameter to change the light quantity, and a controller for controlling a change of the aperture diameter by the light quantity adjustment unit. The controller changes the set value for the minimum aperture diameter of the aperture diameter of the light quantity adjustment unit in accordance with the form of the image pickup device of the image pickup apparatus on which the lens apparatus is mounted.

This application is a continuation of application Ser. No.10/000,084filed Dec. 4, 2001 now U.S. Pat. No. 6,992,720.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an optical apparatus and, moreparticularly, to an optical apparatus including a plurality of imagepickup apparatuses using different forms of image pickup devices, aninterchangeable lens applied to these image pickup apparatuses, and anaperture stop unit for the interchangeable lens.

2. Related Background Art

(1) Conventional Description of General Lens for Video Camera

A conventional most-well-known zoom lens for a video camera is made upof four lens units: a fixed positive lens unit, movable negative lensunit, fixed positive lens unit, and movable positive lens unitsequentially from the object side. In addition to this arrangement, zoomlenses with various lens arrangements are also known.

FIGS. 6A and 6B are sectional views showing the barrel structure of azoom lens having the most popular four-lens-unit arrangement describedabove. FIG. 6B is a sectional view taken along the line 6B-6B in FIG.6A.

The zoom lens is constituted by four lens units: a fixed front lens 201a, a variator lens unit 201 b which moves along the optical axis tochange the magnification, a fixed afocal lens 201 c, and a focus lensunit 201 d which moves along the optical axis to maintain the focalplane and adjusts the focus in changing the magnification.

Guide bars 203, 204 a, and 204 b are arranged parallel to an opticalaxis 205 to guide moving lenses and stop rotation of them. A DC motor206 functions as a drive source for moving the variator lens unit 201 b.FIGS. 6A and 6B show DC motors as a drive source for the variator lensunit 201 b, but a stepping motor may be used similarly to a drive source(to be described later) for moving the focus lens unit 201 d.

The variator lens unit 201 b is held by a holding frame 211. The holdingframe 211 has a press spring 209, and a ball 210 engaged by the force ofthe press spring 209 in a screw groove formed in a screw bar 208. Thescrew bar 208 is rotated and driven by the DC motor 206 via an outputshaft 206 a and gear train 207, thereby moving the holding frame 211 inthe optical axis direction along the guide bar 203.

The focus lens unit 201 d is held by a holding frame 214. A screw member213 is integrated into the holding frame along the optical axis near thesleeve (element fitted in the guide bar to form a guide) of the holdingframe 214. A stepping motor 212 rotates an output shaft 212 a of thestepping motor 212. An external thread formed on the output shaft 212 a,and an internal thread or rack formed in the screw member 213 interlockwith this rotation. By this interlocking rotation, the screw member 213allows the holding frame 214 to move in the optical axis direction alongthe guide bars 204 a and 204 b. A detailed structure of the couplingportion between the holding frame 214 and the screw member 213 isdisclosed in Japanese Patent Application Laid-Open No. 4-136806.

As described above, the interlocking mechanism by the stepping motor 212may be a variator driving mechanism.

One reference position along the optical axis of the holding frame maybe set detectable by a photointerrupter (not shown) and alight-shielding wall integrated with the holding frame, in order todetect the absolute position of a moving lens along the opticaldirection when moving the lens by using this stepping motor 212. In thiscase, a position detection means can be constituted which detects theabsolute position of the holding frame by successively counting thenumber of drive steps applied to the stepping motor 212 after theholding frame is located at the reference position.

In addition to the DC motor 206 and stepping motor 212, some knownarrangements adopt a linear actuator of moving coil (or magnet) typethat is made up of a coil (or magnet) attached to the holding frame anda magnet (or coil) attached to the fixed side.

(2) Conventional Description of Image Pickup Apparatus

FIG. 7 is a block diagram showing the electrical arrangement of aconventional image pickup apparatus. The same reference numerals as inFIGS. 6A and 6B denote parts having the same functions.

In FIG. 7, the image pickup apparatus comprises a solid-state imagepickup device 221 such as a CCD. A zoom drive source 222 for thevariator lens unit 201 b includes the DC motor 206, the gear traininterlocked with the DC motor 206, and the screw bar 208 in FIG. 6A.Alternatively, the zoom drive source 222 is comprised of a steppingmotor similarly to the drive source of the focus lens unit 201 d inFIGS. 6A and 6B. A drive source 223 for the focus lens unit 201 dincludes the stepping motor 212, the output shaft with an externalthread, and the screw member 213 integrated with the holding frame alongthe optical axis.

The image pickup apparatus further comprises an aperture stop drivesource 224. A zoom encoder 225 and focus encoder 227 detect the absolutepositions of the variator lens unit 201 b and focus lens unit 201 dalong the optical axis. When the variator drive source is realized by aDC motor, as shown in FIGS. 6A and 6B, an absolute position encoder suchas a volume (not shown in FIGS. 6A and 6B) may be used. This encoder maybe of magnetic type. When a stepping motor is used for the drive source,it is general to locate the holding frame at a reference position andsuccessively count the number of operation pulses input to the steppingmotor, as described above.

An aperture stop encoder 226 is, e.g., one which incorporates a Hallelement in a motor serving as an aperture stop source and detects therelationship in rotational position between the rotor and the stator. Acamera signal process circuit 228 performs predetermined amplificationand gamma correction for an output from the CCD 221. A contrast signalof an image signal having undergone the predetermined process passesthrough an AE gate 229 and AF gate 230. That is, these gates set fromthe entire frame a signal extraction range optimal for determining theexposure and adjusting the focus. The gate size is variable and in somecases a plurality of gates are adopted, but a detailed descriptionthereof will be omitted for descriptive convenience.

An AF signal process circuit 231 for AF (Auto Focus) generates one or aplurality of outputs concerning the high-frequency component of an imagesignal. The image pickup apparatus has a zoom switch 233. A zoomtrucking memory 234 stores information about a prospective focus lensposition corresponding to the object distance and variator lens positionin changing the magnification. The zoom trucking memory may be a memoryin the CPU. A CPU 232 controls various circuits.

In this arrangement, when the user operates the zoom switch 233, the CPU232 drives and controls the zoom drive source 222 and focus drive source223 such that the current absolute position of the variator lens unit201 b along the optical axis as the detection result of the zoom encoder225 coincides with a calculated prospective position of the variatorlenses, and the current absolute position of the focus lens unit 201 dalong the optical axis as the detection result of the focus encoder 227coincides with a calculated prospective position of the focus lenses, soas to maintain a predetermined positional relationship between thevariator lens unit 201 b and the focus lens unit 201 d that iscalculated based on information in the zoom trucking memory 234.

In autofocus operation, the CPU 232 drives and controls the focus drivesource 223 such that an output from the AF signal process circuit 231exhibits a peak.

To obtain correct exposure, the CPU 232 drives and controls the aperturestop source 224 and controls the aperture diameter based on an outputfrom aperture stop encoder 226 so as to set the average value of outputsof Y signals (brightness signals) having passed through the AE gate 229to a predetermined value.

(3) Conventional Description of Television Signal Autofocus Method inImage Pickup Apparatus with Above Arrangement

This method has no drawback such as necessary for without any cost foranother sensor because an autofocus sensor also serves as the imagepickup device of an image pickup apparatus. In this method, since animage state on an imaging plane is directly detected, for example, evenwhen a temperature change expands or contracts the lens barrel to changethe focal position, a correct focus position can be detected inaccordance with this change.

FIG. 8 shows this principle. The abscissa represents the lens positionfor focus adjustment, and the ordinate represents the high-frequencycomponent (focal point voltage) of an image pickup signal. The focalpoint voltage exhibits a peak at a position indicated by the arrow inFIG. 8. This position A is an in-focus lens position.

An example of obtaining the focal point voltage F will be described.

FIG. 9A shows an actual image pickup field having a view angle 320, arange 318 for extracting an image pickup signal for autofocusadjustment, and an object 319 to be sensed.

In FIG. 9B, (a) represents the state of the object in the image pickupsignal extraction range, and (b) represents an image pickup (brightness)signal (Y signal) of the object in (a). This signal is differentiatedinto a waveform (c), and absolutized into a waveform (d). A sampled andheld signal (e) of the resultant signal is the focal point voltage F.This utilizes the fact that particularly the high-frequency component ofthe contrast signal of an object to be sensed maximizes in an in-focusstate. The focal point voltage generation method includes variousmethods in addition to this method.

A high-pass filter is often used to extract only a high-frequencycomponent. It is also known that a filter having several kinds ofcharacteristics is prepared, focal point voltages are set for aplurality of frequencies, and a correct focus is secured based on thesepieces of information.

FIG. 10 is a view showing the main part of an image pickup apparatus asa combination of such an autofocus adjustment apparatus and an innerfocus lens.

An image pickup device such as a CCD is located at an imaging position505. A brightness signal Y is generated by a signal process circuit (notshown) or the like on the basis of an output from the image pickupdevice, and information within a predetermined frame is received by anAF circuit 521. The AF circuit 521 obtains a focal point voltage by theabove-described method or the like. An in-focus or out-of-focus state,and a rear- or front-focus state for the out-of-focus state aredetermined based on the focal point voltage value, the driving directionof a focus lens 504B, and the sign of a change in focal point voltageupon drive. A focus lens drive motor 522 is driven in a predetermineddirection on the basis of the determination result. In FIG. 10, a frontlens 501, variator lens 502, and afocal lens 504A are arranged.

This autofocus method is called a “television signal autofocus” in whichthe image sensor of the image pickup apparatus also serves as anautofocus sensor. Thus, the imaging state of the imaging plane isdirectly measured, and the focal state can always be grasped with highprecision. To determine a far- or near-focus state by this method whenthe focus greatly deviates, the focus lens is vibrated by apredetermined small amount along the optical axis to measure an increaseor decrease in focal point voltage signal. Even if the signal increaseor decrease cannot be obtained, the focus lens is driven in eitherdirection to measure a signal change. In this method, a relatively longtime is taken from an out-of-focus state to an in-focus state.

(4) Conventional Description of Zoom Trucking

As shortly described in (2), the focus lens during zoom takes adifferent trucking locus in accordance with the object distance infocusing by lenses behind a variator lens in an image pickup apparatushaving the arrangement as shown in FIG. 7. For this reason, the focusmust be maintained even during zoom by measuring the absolute positionsof the variator and focus lenses along the optical axis at the start ofzoom, specifying a prospective positional relationship between the twolenses during zoom, and performing operation so as to keep thesepositions. This operation is called zoom trucking.

As this method, Japanese Patent Application Laid-Open No. 1-321416discloses the following method. More specifically, focus lens positionsfor a plurality of variator lens positions between the wide angle endand the telephoto end are stored in accordance with a plurality ofobject distances. At the start of zoom, the current variator and focuslens positions are checked on map information stored in a memory meansin a microcomputer. Interpolation calculation is executed based on datastored nearest to the front-focus side from the obtained point with thesame focal length, and data stored nearest to the rear-focus side. Focuslens positions are calculated for respective focal lengths (variatorlens positions).

FIG. 11 is a view of the trucking curve (locus) near the telephoto end.The abscissa represents the variator lens position; Vn, the telephotoend position; and the ordinate, the focus lens position.

For example, P1, P4, P7, and P10 are stored for an infinite distance,and P2, P5, P8, and P11 are stored for 10 m. If the lens is moved forzoom toward the wide angle end while the focus lens position is at pointP (object distance is between 10 m and the infinity at the telephotoend), the positional relationship between the variator lens and thefocus lens is controlled to sequentially track P_(A), P_(B), and P_(C)from P. The positions P_(A) to P_(C) are positions where theinterpolation ratio between upper and lower stored loci LL1 and LL2 isconstant.

(5) Conventional Description of Lens-Interchangeable Image Pickup System

It is well known that a lens can be interchanged from an image pickupapparatus body in an image pickup apparatus having the abovearrangement.

FIG. 12 is a block diagram showing an example of a lens-interchangeableimage pickup system. A zoom lens made up of four, positive, negative,positive, and positive lens units from the object side will beexemplified, similar to the above description, but the image pickupsystem may employ another arrangement.

In FIG. 12, the lens side comprises a fixed front lens 111, a variatorlens 112 which moves along the optical axis to change the magnification,an aperture stop unit 136, and a fixed afocal lens 113. A focus lens 114performs focus operation when the object distance changes, and alsofunctions as a compensator during zoom. Drive sources 145, 413, and 137are for the variator lens 112, aperture stop unit 136, and focus lens114, respectively, and are driven and controlled by a lens microcomputer410 via drive circuits 161, 414, and 162, respectively.

In this example, the image pickup apparatus body side comprises threeimage pickup devices 303 to 305 such as CCDs. Their image pickup signalsare amplified by amplifiers 405 to 407, and processed into an imagepickup signal by an signal process circuit 152. The image pickup signalis transmitted to an apparatus microcomputer 409.

The two microcomputers 409 and 410 are connected via a transmission pathby contact between contacts 318 and 307. The microcomputers 409 and 410exchange various signals through this transmission path.

If the signal process circuit 152 generates a focal point voltage forthe above-mentioned television signal autofocus in this arrangement, theinformation is transmitted from the apparatus microcomputer 409 to thelens microcomputer 410. The lens microcomputer 410 determines anin-focus or out-of-focus state on the basis of the signal information,or determines the direction and drive speed of the focus lens 114depending on the direction (rear- or front-focus state) and degree ofthe out-of-focus state. Then, the lens microcomputer 410 drives thedrive source 137 via the drive circuit 162.

(6) Conventional Description of Image Pickup Device

An image pickup device such as a CCD is attaining a diagonal length ofabout 6 mm or 4 mm that is called ⅓″ or ¼″ in a consumer video camera.The image pickup device has 310,000 pixels within this size. A digitalstill camera uses a so-called megapixel CCD of 2,000,000 pixels withinabout ½″ (diagonal length: about 8 mm), and is ensuring an image qualityalmost equal to that obtained by a conventional silver halide camera forat least a popular small print size.

The diameter of permissible circle of confusion is about 12 to 15 μm inthe video camera and about 7 to 8 μm in the digital still camera. Thisis a very small numerical value in comparison with a diameter ofpermissible circle of confusion of 33 to 35 μm for a 135 film formatbecause the diagonal size of the frame is much smaller than a 43-mmdiagonal size of a silver halide camera. This value is predicted todecrease more in the future.

From another viewpoint, the focal length for obtaining the same angle ofview can be shortened in an image pickup apparatus using such a CCD incomparison with a 135 film camera because of a small image size. Theangle of view obtained at a standard focal length of 40 mm by the 135film is 4 mm in a camera using a ¼″ CCD. Thus, the depth of field inimage pickup with the same F value is very long in the image pickupapparatus using the CCD.

As is well known, the depth of field is determined by “permissiblecircle of confusion×F”. For example, for F=2, the depth of field is“0.035×2=0.07 mm” in a 135 film camera, but “0.07×2=0.14 mm” in a ½″digital still camera which is ⅕ that of the 135 film camera.

As for an image pickup device such as a ⅓″ CCD having the same diagonalline, e.g., 6 mm, there are known various forms of image pickup devicessuch as CCDs including image pickup devices which attain higherresolution by increasing the number of pixels to one million pixels orin the future two to several million pixels, and image pickup deviceswhich ensure the pixel size, sensitivity, and dynamic range whileslightly suppressing the number of pixels.

In this manner, a CCD to be used changes depending on whether highresolution is important or the sensitivity or dynamic range isimportant. In addition, the form is also changed depending on whetherthe optical path must be shielded by a mechanical shutter during chargetransfer (read of all pixels or not).

For example, a film camera selectively uses a low-sensitivity,ultra-fine-grain film which puts emphasis on high-resolution imagepickup, and a high-sensitivity film with lower resolution in accordancewith the intended use. Similarly, a CCD to be used also changesdepending on the image pickup purpose.

As is well known, the optical diffraction phenomenon occurs when lightpasses through a small hole. In the image pickup apparatus, the imagequality is readily decreased by the diffraction phenomenon with the useof a megapixel CCD of a small pixel pitch. For example, even with thesame ⅓″ CCD, a video camera of a large pixel pitch (small number ofpixels) can be practically used up to F16 or F22, but a digital cameraof 1,000,000 pixels can only be used up to F8 or F11, and a digitalcamera of 2,000,000 pixels can only be used up to F5.6 or F8. Althoughthese numerical values are merely an example, the F value which causesdiffraction of a small aperture changes to a smaller F value as theresolution qualitatively increases.

To prevent this, the F value as a limit aperture diameter is set to aunique value in a lens-integrated image pickup apparatus such as a videocamera so as not to use a smaller F value.

However, when the same lens interchangeable from an image pickupapparatus can be mounted on different image pickup apparatuses withimage pickup devices, such as a video camera, a digital still camerawith a higher-resolution CCD, and a digital still camera with highersensitivity, or when the image pickup device can be interchanged fromthe image pickup apparatus in accordance with the intended use, thefollowing problems arise unless the F value as a limit aperture diameteris set changeable in accordance with the CCD form (e.g., the numericalvalue of the pixel pitch). a) The image degrades due to the diffractionphenomenon depending on a selected CCD. b) The exposure adjustable rangeby the aperture stop unit is excessively limited depending on a selectedCCD.

SUMMARY OF THE INVENTION

It is the first object of the present invention to provide a lens orimage pickup system which prevents image degradation caused by thediffraction phenomenon without limiting the exposure adjustable range byan aperture member even if an optimal image pickup apparatus body isselectively used for a single lens in accordance with the intended usesuch as high-sensitivity image pickup, high-resolution image pickup, orimage pickup of a moving picture.

It is the second object of the present invention to provide an imagepickup system which prevents image degradation caused by the diffractionphenomenon without limiting the exposure adjustable range by an aperturestop unit even if an optimal image pickup system apparatus is mounted onan apparatus body in accordance with the intended use such ashigh-sensitivity image pickup, high-resolution image pickup, or imagepickup of a moving picture.

It is the third object of the present invention to provide a lens orimage pickup system capable of issuing a warning to avoid imagedegradation in advance when an aperture diameter smaller than a limitvalue must be used based on information concerning arbitrary setexposure control.

To achieve the above object, according to the present invention, thereis provided a lens apparatus interchangeably mounted on a plurality ofimage pickup apparatuses having different forms of image pickup devices,comprising

an image pickup optical unit,

a light quantity adjustment unit inserted in an optical axis of theimage pickup optical unit, the light quantity adjustment unit changingan aperture diameter to change a light quantity, and

a controller for controlling a change of the aperture diameter by thelight quantity adjustment unit,

wherein the controller changes a set value of the light quantityadjustment unit for a minimum aperture diameter of the aperture diameterin accordance with the form of the image pickup device of the imagepickup apparatus on which the lens apparatus is mounted.

According to the present invention, there is provided an opticalapparatus including at least any one of a plurality of image pickupapparatuses having different forms of image pickup devices, and a lensapparatus interchangeably mounted on the one image pickup apparatus, theone image pickup apparatus and the lens apparatus having contacts forperforming transmission between the one image pickup apparatus and thelens apparatus, the optical apparatus comprising

an image pickup optical unit which is included in the lens apparatus,

a light quantity adjustment unit inserted in an optical path of theimage pickup optical unit, the light quantity adjustment unit changingan aperture diameter to change a light quantity, and

a controller for controlling a change of the aperture diameter by thelight quantity adjustment unit, the controller obtaining informationconcerning the form of the image pickup device from the image pickupapparatus by transmission via the contacts,

wherein the controller changes a set value of the light quantityadjustment unit for a minimum aperture diameter of the aperture diameterin accordance with the information concerning the form of the imagepickup device of the image pickup apparatus that is obtained by thetransmission.

According to the present invention, there is provided an opticalapparatus including any one of a plurality of image pickup units whichinclude image pickup devices and have different forms of the imagepickup devices, and a main body unit which includes an image pickupoptical unit on which the one image pickup unit is mounted to form animage on the image pickup device, and a memory part for storing an imagepickup signal from the image pickup unit, the one image pickup unit andthe main body unit having contacts for performing transmission betweenthe one image pickup unit and the main body unit, the optical apparatuscomprising

a light quantity adjustment unit inserted in an optical path of theimage pickup optical unit, the light quantity adjustment unit changingan aperture diameter to change a light quantity, and

a controller for controlling a change of the aperture diameter by thelight quantity adjustment unit, the controller obtaining informationconcerning the form of the image pickup device from the image pickupunit by transmission via the contacts,

wherein the controller changes a set value of the light quantityadjustment unit for a minimum aperture diameter of the aperture diameterin accordance with the information concerning the form of the imagepickup device of the image pickup unit that is obtained by thetransmission.

According to the present invention, there is provided a lens apparatusinterchangeably mounted on a plurality of image pickup apparatuses whichhave different forms of image pickup devices and a plurality of imagepickup modes, comprising

an image pickup optical unit,

a light quantity adjustment unit inserted in an optical axis of theimage pickup optical unit, the light quantity adjustment unit changingan aperture diameter to change a light quantity, and

a controller for controlling a change of the aperture diameter by thelight quantity adjustment unit,

wherein the controller changes a set value of the light quantityadjustment unit for a minimum aperture diameter of the aperture diameterin accordance with the form of the image pickup device in a preset imagepickup mode out of the plurality of image pickup modes of the imagepickup apparatus on which the lens apparatus is mounted.

According to the present invention, there is provided a lens apparatusinterchangeably mounted on a plurality of image pickup apparatuses whichhave different forms of image pickup devices and a plurality of imagepickup modes, comprising

an image pickup optical unit,

a light quantity adjustment unit inserted in an optical axis of theimage pickup optical unit, the light quantity adjustment unit changingan aperture diameter to change a light quantity, and

a controller for controlling a change of the aperture diameter by thelight quantity adjustment unit,

wherein the controller changes a set value of the light quantityadjustment unit for a minimum aperture diameter of the aperture diameterin accordance with the form of the image pickup device of the imagepickup apparatus on which the lens apparatus is mounted, and

the controller inhibits setting an aperture value of which an aperturediameter becomes smaller than the changed set value of the minimumaperture diameter in an aperture priority image pickup mode out of theplurality of image pickup modes of the image pickup apparatus.

According to the present invention, there is provided a lens apparatusinterchangeably mounted on a plurality of image pickup apparatuses whichhave different forms of image pickup devices and a plurality of imagepickup modes, comprising

an image pickup optical unit,

a light quantity adjustment unit inserted in an optical axis of theimage pickup optical unit, the light quantity adjustment unit changingan aperture diameter to change a light quantity, and

a controller for controlling a change of the aperture diameter by thelight quantity adjustment unit,

wherein the controller changes a set value of the light quantityadjustment unit for a minimum aperture diameter of the aperture diameterin accordance with the form of the image pickup device of the imagepickup apparatus on which the lens apparatus is mounted, and

the controller issues a warning from the image pickup apparatus when anaperture value or shutter speed with which an aperture diameter becomessmaller than the changed set value of the minimum aperture diameter isset in an image pickup mode of arbitrarily changing the aperture valueor shutter speed out of the plurality of image pickup modes of the imagepickup apparatus.

According to the present invention, there is provided an opticalapparatus including at least any one of a plurality of image pickupapparatuses which have different forms of image pickup devices and aplurality of image pickup modes, and a lens apparatus interchangeablymounted on the one image pickup apparatus, the one image pickupapparatus and the lens apparatus having contacts for performingtransmission between the one image pickup apparatus and the lensapparatus, the optical apparatus comprising

an image pickup optical unit which is included in the lens apparatus,

a light quantity adjustment unit inserted in an optical path of theimage pickup optical unit, the light quantity adjustment unit changingan aperture diameter to change a light quantity, and

a controller for controlling a change of the aperture diameter by thelight quantity adjustment unit, the controller obtaining informationconcerning the form of the image pickup device and informationconcerning the image pickup mode from the image pickup apparatus bytransmission via the contacts,

wherein the controller changes a set value of the light quantityadjustment unit for a minimum aperture diameter of the aperture diameterin accordance with the information concerning the form of the imagepickup device of the image pickup apparatus that is obtained by thetransmission when the information concerning the image pickup modeobtained by the transmission represents a preset image pickup mode outof the plurality of image pickup modes.

According to the present invention, there is provided an opticalapparatus including any one of a plurality of image pickup units whichinclude image pickup devices and have different forms of the imagepickup devices, and a main body unit which has a plurality of imagepickup modes and includes an image pickup optical unit on which the oneimage pickup unit is mounted to form an image on the image pickupdevice, and a memory part for storing an image pickup signal from theimage pickup unit, the one image pickup unit and the main body unithaving contacts for performing transmission between the one image pickupunit and the main body unit, the optical apparatus comprising

a light quantity adjustment unit inserted in an optical axis of theimage pickup optical unit, the light quantity adjustment unit changingan aperture diameter to change a light quantity, and

a controller for controlling a change of the aperture diameter by thelight quantity adjustment unit, the controller obtaining informationconcerning the form of the image pickup device and informationconcerning the image pickup mode from the image pickup unit bytransmission via the contacts,

wherein the controller changes a set value of the light quantityadjustment unit for a minimum aperture diameter of the aperture diameterin accordance with the information concerning the form of the imagepickup device of the image pickup unit that is obtained by thetransmission when the information concerning the image pickup modeobtained by the transmission represents a preset image pickup mode outof the plurality of image pickup modes.

According to the present invention, there is provided an opticalapparatus including at least any one of a plurality of image pickupapparatuses which have different forms of image pickup devices and aplurality of image pickup modes, and a lens apparatus interchangeablymounted on the one image pickup apparatus, the one image pickupapparatus and the lens apparatus having contacts for performingtransmission between the one image pickup apparatus and the lensapparatus, the optical apparatus comprising

an image pickup optical unit which is included in the lens apparatus,

a light quantity adjustment unit inserted in an optical path of theimage pickup optical unit, the light quantity adjustment unit changingan aperture diameter to change a light quantity, and

a controller for controlling a change of the aperture diameter by thelight quantity adjustment unit, the controller obtaining informationconcerning the form of the image pickup device and informationconcerning the image pickup mode from the image pickup apparatus bytransmission via the contacts,

wherein the controller changes a set value of the light quantityadjustment unit for a minimum aperture diameter of the aperture diameterin accordance with the information concerning the form of the imagepickup device of the image pickup apparatus that is obtained by thetransmission, and

the controller inhibits setting an aperture value of which an aperturediameter becomes smaller than the changed set value of the minimumaperture diameter when the image pickup mode obtained by thetransmission is an aperture priority image pickup mode out of theplurality of image pickup modes of the image pickup apparatus.

According to the present invention, there is provided an opticalapparatus including at least any one of a plurality of image pickupapparatuses which have different forms of image pickup devices and aplurality of image pickup modes, and a lens apparatus interchangeablymounted on the one image pickup apparatus, the one image pickupapparatus and the lens apparatus having contacts for performingtransmission between the one image pickup apparatus and the lensapparatus, the optical apparatus comprising

an image pickup optical unit which is included in the lens apparatus,

a light quantity adjustment unit inserted in an optical path of theimage pickup optical unit, the light quantity adjustment unit changingan aperture diameter to change a light quantity, and

a controller for controlling a change of the aperture diameter by thelight quantity adjustment unit, the controller obtaining informationconcerning the form of the image pickup device and informationconcerning the image pickup mode from the image pickup apparatus bytransmission via the contacts,

wherein the controller changes a set value of the light quantityadjustment unit for a minimum aperture diameter of the aperture diameterin accordance with the information concerning the form of the imagepickup device of the image pickup apparatus that is obtained by thetransmission, and

the controller transmits information representing a warning to the imagepickup apparatus via the contacts when the image pickup mode obtained bythe transmission is an image pickup mode of arbitrarily changing anaperture value or shutter speed, and when the aperture value or shutterspeed with which an aperture diameter becomes smaller than the changedset value of the minimum aperture diameter is set.

According to the present invention, there is provided an opticalapparatus including any one of a plurality of image pickup units whichinclude image pickup devices and have different forms of the imagepickup devices, and a main body unit which has a plurality of imagepickup modes and includes an image pickup optical unit on which the oneimage pickup unit is mounted to form an image on the image pickupdevice, and a memory part for storing an image pickup signal from theimage pickup unit, the one image pickup unit and the main body unithaving contacts for performing transmission between the one image pickupunit and the main body unit, the optical apparatus comprising

a light quantity adjustment unit inserted in an optical axis of theimage pickup optical unit, the light quantity adjustment unit changingan aperture diameter to change a light quantity, and

a controller for controlling a change of the aperture diameter by thelight quantity adjustment unit, the controller obtaining informationconcerning the form of the image pickup device and informationconcerning the image pickup mode from the image pickup unit bytransmission via the contacts,

wherein the controller changes a set value of the light quantityadjustment unit for a minimum aperture diameter of the aperture diameterin accordance with the information concerning the form of the imagepickup device of the image pickup unit that is obtained by thetransmission, and

the controller inhibits setting an aperture value of which an aperturediameter becomes smaller than the changed set value of the minimumaperture diameter when the image pickup mode obtained by thetransmission is an aperture priority image pickup mode out of theplurality of image pickup modes.

According to the present invention, there is provided an opticalapparatus including any one of a plurality of image pickup units whichinclude image pickup devices and have different forms of the imagepickup devices, and a main body unit which has a plurality of imagepickup modes and includes an image pickup optical unit on which the oneimage pickup unit is mounted to form an image on the image pickupdevice, and a memory part for storing an image pickup signal from theimage pickup unit, the one image pickup unit and the main body unithaving contacts for performing transmission between the one image pickupunit and the main body unit, the optical apparatus comprising

a light quantity adjustment unit inserted in an optical axis of theimage pickup optical unit, the light quantity adjustment unit changingan aperture diameter to change a light quantity, and

a controller for controlling a change of the aperture diameter by thelight quantity adjustment unit, the controller obtaining informationconcerning the form of the image pickup device and informationconcerning the image pickup mode from the image pickup unit bytransmission via the contacts,

wherein the controller changes a set value of the light quantityadjustment unit for a minimum aperture diameter of the aperture diameterin accordance with the information concerning the form of the imagepickup device of the image pickup unit that is obtained by thetransmission, and

the controller transmits information representing a warning to the imagepickup apparatus via the contacts when the image pickup mode obtained bythe transmission is an image pickup mode of arbitrarily changing anaperture value or shutter speed, and when the aperture value or shutterspeed with which an aperture diameter becomes smaller than the changedset value of the minimum aperture diameter is set.

The above and other objects, features, and advantages of the presentinvention will be apparent from the following description in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the circuit arrangement of an opticalapparatus according to the first embodiment of the present invention;

FIG. 2 is a table for explaining transmission processes between a lensmicrocomputer and an apparatus microcomputer in the first embodiment ofthe present invention;

FIG. 3 is a block diagram showing the circuit arrangement of an opticalapparatus according to the second embodiment of the present invention;

FIG. 4 is a flow chart showing the operation of the main part of a lensmicrocomputer in an optical apparatus according to the third embodimentof the present invention;

FIG. 5 is a flow chart showing the operation of the main part of acamera microcomputer in the optical apparatus according to the thirdembodiment of the present invention;

FIGS. 6A and 6B are sectional views showing the structure of a generallens for a video camera;

FIG. 7 is a block diagram showing the circuit arrangement of a generalimage pickup apparatus;

FIG. 8 is a graph for explaining a television signal autofocus method inthe image pickup apparatus of FIG. 7;

FIGS. 9A and 9B are views for explaining the television signal autofocusmethod in the image pickup apparatus of FIG. 7;

FIG. 10 is a view for explaining a general zoom trucking method in animage pickup apparatus;

FIG. 11 is a graph for explaining the zoom trucking method; and

FIG. 12 is a block diagram showing the arrangement of a conventionalimage pickup system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described indetail below with reference to the accompanying drawings.

First Embodiment

FIG. 1 is a block diagram showing the arrangement of the main part of alens-interchangeable image pickup system according to the firstembodiment of the present invention. The same reference numerals as inFIG. 12 denote parts having the same functions.

In FIG. 1, the image pickup apparatus body side comprises a CCD 1serving as an image pickup device, and a CCD drive circuit 2 for drivingthe CCD 1. A mode select element 3 is used to select an image pickupmode such as an auto mode, portrait mode, aperture priority mode, andshutter priority mode. A manual shutter speed set element 4 is used toselect an arbitrary shutter speed. A manual aperture value set element 5is used to set an arbitrary aperture value. The image pickup apparatusalso comprises an AE gate 9.

The lens side comprises a fixed front lens 111, a variator lens 112which moves along the optical axis to change the magnification, anaperture stop unit 136 serving as a light quantity adjustment unit, anda fixed afocal lens 113. A focus lens 114 performs focus operation whenthe object distance changes, and also functions as a compensator duringzoom. A drive source 413 is for the aperture stop unit 136 and is drivenand controlled by a lens microcomputer 410 via a drive circuit 414.

The image pickup apparatus body side comprises the above-described CCD1. An image pickup signal is amplified by an amplifier (not shown), andprocessed into an image pickup signal by an signal process circuit 152.The image pickup signal is transmitted to an apparatus microcomputer409.

The two microcomputers 409 and 410 are connected via a transmission pathby contact between contacts 318 and 307. The microcomputers 409 and 410exchange various signals through this transmission path.

If the signal process circuit 152 generates a focal point voltage forthe above-mentioned television signal autofocus in the abovearrangement, the information is transmitted from the apparatusmicrocomputer 409 to the lens microcomputer 410. The lens microcomputer410 determines an in-focus or out-of-focus state on the basis of thesignal information, or determines the driving direction and drivingspeed of the focus lens 114 depending on the direction (rear- orfront-focus state) and degree of the out-of-focus state. Then, the lensmicrocomputer 410 drives the lens.

In the first embodiment, an image pickup apparatus body (camera body)419 transmits information concerning the pixel pitch of the CCD to alens 418. In accordance with this information, the lens microcomputer410 sets the minimum limit F value of a small aperture (limit valuewhich does not allow the aperture stop unit to change to a smalleraperture diameter).

In FIG. 1, the apparatus microcomputer 409 of the image pickup apparatusbody 419 stores information concerning the pixel pitch of the CCD 1 as amounted image pickup device in a pixel pitch information memorizing part409 a such as a memory in advance. If the lens 418 is newly mounted onthe image pickup apparatus body 419 or the main power of the imagepickup apparatus body is turned on (ON), a reset signal is transmittedbetween the apparatus microcomputer 409 and the lens microcomputer 410.Transmission is done via the mount contacts 307 and 318. FIG. 1schematically shows CTL (Camera To Lens) operation and LTC (Lens ToCamera) operation via the two contacts, but the number of contacts andthe transmission direction are not limited to them.

In reset transmission operation, information concerning the pixel pitchof the CCD 1 is read in the lens microcomputer 410. The lensmicrocomputer 410 internally sets an Fth value as the limit F value of ausable small aperture in exposure control in accordance with theinformation. (Reset operation in power-ON is described in the item“POWER SUPPLY ON” shown in the table of FIG. 2.)

As described above, the apparatus microcomputer 409 transmits to thelens 418 necessary information including pixel pitch information storedin the pixel pitch information memorizing part 409 a. Along with this,pixel pitch information is sent by CTL transmission (transmission fromthe camera (image pickup apparatus) to the lens). Upon reception of theinformation including the pixel pitch information, the lensmicrocomputer 410 determines an Fth value as the limit F value of asmall aperture. For example, if information “pixel pitch: 4 μm” is sent,“F8=Fth” is set by the table present within the lens microcomputer 410,or Fth is calculated by an equation using the numerical value of thepixel pitch as a variable. In some cases, the Fth value is sent at thebeginning by CTL transmission. At this time, the sent numerical value isdirectly set. If the CCD size is known in advance, the pixel pitch canbe attained from the number of pixels. In this case, number-of-pixelinformation may be set by CLT transmission.

Considering Fth as F value information set in accordance with the pixelpitch value, i.e., as an F-number (F No.), the output value of anaperture stop encoder 163 that corresponds to the F-number must be set.For this purpose, the lens microcomputer 410 holds data representing therelationship between the F-number and an output from the aperture stopencoder 163 (value obtained by A/D-converting the output is alsopossible). In practice, the minimum aperture limit is obtained by anencoder output corresponding to Fth.

The aperture stop encoder 163 often uses a magnetic sensor incorporatedin an IG motor 413. In LTC transmission (transmission from the lens tothe camera), the lens microcomputer 410 notifies the apparatusmicrocomputer 409 that the reset signal has been transmitted without anyproblem. Then, reset operation is completed.

According to the first embodiment, even when a plurality of image pickupapparatus bodies with different pixel pitches of image pickup devicessuch as CCDs are prepared for a single lens, each image pickup apparatusbody stores information concerning a mounted image pickup device, e.g.,information about the number of pixels and the pixel pitch, and F valueinformation set in accordance with the pixel pitch value. For example,after the image pickup apparatus body is mounted on the lens, the lenstransmits information concerning the image pickup device. The lens sidecan change the set value of the aperture stop unit 136 concerning theuse limit of a small aperture on the basis of the information.

This arrangement can prevent the problem that the image degrades due tosmall-aperture diffraction depending on an image pickup apparatus bodyto be combined (more specifically, depending on a CCD). An image can beappropriately picked up even by an image pickup system (opticalapparatus) constituted by mounting a single lens on any one of imagepickup apparatus bodies having different forms of image pickup devices.

Second Embodiment

The first embodiment shown in FIG. 1 has exemplified an image pickupsystem as a combination of an image pickup apparatus body andinterchangeable lens. As shown in FIG. 3, the second embodiment of thepresent invention will exemplify an image pickup system (opticalapparatus) as a combination of an image pickup unit 502 including a CCD1 serving as an image pickup device, a signal process circuit 152, a CCDdrive (driver) circuit 2, and a CCD block microcomputer 7, and a mainbody unit 501 including lenses 111 to 114, a microcomputer 8, and amemory part 6. That is, the second embodiment provides an image pickupsystem (optical apparatus) constituted by combining any one of imagepickup units 502 having different forms of image pickup devices to themain body unit 501.

In FIG. 3, the CCD block microcomputer 7 stores information concerningthe pixel pitch of the CCD 1 in a memory part (not shown) such as amemory. The CCD block microcomputer 7 transmits signals to the apparatusmicrocomputer 8 via contact blocks 318 and 307, as shown in FIG. 1. Inreset transmission, the CCD block microcomputer 7 transmits pixel pitchinformation of the CCD 1. The apparatus microcomputer 8 can control theaperture stop by changing the aperture set value of an aperture stopunit 136 concerning the use limit of a small aperture on the basis ofthe pixel pitch information of the mounted image pickup unit 502regardless of the form of the image pickup device thereof. Thus, imagedegradation by the diffraction phenomenon can be prevented.

Third Embodiment

An image pickup system (optical apparatus) according to the thirdembodiment of the present invention will be described. Either of theimage pickup system arrangements in FIGS. 1 and 3 can be applied, andthe third embodiment will be exemplified using the arrangement of FIG.1.

If the image pickup mode is set to an auto mode or portrait mode by amode select element 3 in an image pickup system having the arrangementof FIG. 1, settings of the shutter speed and aperture value by setelements 4 and 5 are ignored or the shutter speed and aperture valuecannot be set.

This operation is summarized in the item “AUTO MODE OPERATION” in FIG.2.

In a situation where the exposure can be controlled in a generalaperture stop, an apparatus microcomputer 409 calculates a difference ΔAbetween the average value and target value of a brightness signal in anAE gate 9. For example, a positive difference ΔA means overexposure, anda negative difference ΔA means underexposure. The exposure is determinedto be correct for “|ΔA|<ΔAth” (ΔAth: the threshold of ΔA), but adetailed description thereof will be omitted. ΔA is transmitted to alens microcomputer 410 by CTL transmission. The lens microcomputer 410checks the sign of transmitted ΔA, and drives an aperture stop unit 136in a closing direction for a sign “+” and in an opening direction for asign “−”. If necessary, the lens microcomputer 410 transmits the currentF value by LTC transmission. This feedback control keeps ΔA=0 (or|ΔA|<ΔAth; ΔAth is the threshold of ΔA), obtaining correct exposure.

If overexposure occurs even after the aperture value reaches Fth whichis the limit F value of a small aperture, the operation in the item“APERTURE LIMIT” in FIG. 2 is executed. In CTL transmission, ΔA istransmitted. The lens microcomputer 410 detects that ΔA is positive(overexposure) but the aperture value has reached Fth. Since theaperture stop cannot be changed to a smaller aperture value, the lensmicrocomputer 410 notifies the apparatus microcomputer 409 of F(aperture value)=Fth (limit aperture value of a small aperture). Becauseof F=Fth and positive ΔA, the apparatus microcomputer 409 changes theshutter speed of a shutter (not shown) to a higher one, obtainingcorrect exposure. The shutter (not shown) includes a shutter mechanismon the optical axis in front of the CCD 1 or on the optical axis of thelenses 111 to 114, and an electronic shutter function of changing thelight accumulation time of light-receiving pixels on the CCD 1.

FIGS. 4 and 5 are flow charts showing processes by the lensmicrocomputer 410 and apparatus microcomputer 409 during theabove-described operation. More specifically, FIGS. 4 and 5 show theoperation when an auto exposure adjustment image pickup mode such as anauto mode or portrait mode is selected. When the third embodiment isapplied to an image pickup system (optical system) as shown in FIG. 3,the camera microcomputer 8 in FIG. 3 performs the following operation.

In the auto mode, the camera automatically sets the exposure. In theportrait mode, the camera automatically sets such exposure as toemphasize a main object such as a person.

The process by the lens microcomputer 410 will be explained withreference to the flow chart of FIG. 4.

In step #1, the lens microcomputer 410 receives a ΔA value transmittedby CTL transmission. In step #2, the lens microcomputer 410 checkswhether ΔA=0 (in some cases, |ΔA|<ΔAh) holds. If YES in step #2, thelens microcomputer 410 returns to step #1.

If NO in step #2, the lens microcomputer 410 advances to step #3 tocheck overexposure or underexposure on the basis of sign determination.If underexposure is determined in step #3, the lens microcomputer 410advances to step #4 to check whether the aperture stop unit 136 reachesan aperture limit. If NO in step #4, the lens microcomputer 410 shiftsto step #5 to drive the aperture stop unit 136 in an opening direction.If YES in step #4, the lens microcomputer 410 shifts from step #4 to #6to transmit to the apparatus microcomputer 409 that the aperture stopattains the limit value.

If overexposure is determined in step #3, the lens microcomputer 410advances to step #7 to check whether the Fth value set based on pixelpitch information of the CCD 1 in reset transmission and the current Fvalue satisfy “F=Fth” (in practice, not the F value but an encoderoutput is used for equivalent comparison). If F=Fth does not hold (not asmall aperture), the lens microcomputer 410 shifts to step #9 to closethe aperture stop unit 136. If F=Fth holds, the lens microcomputer 410shifts to step #8 to transmit “F=Fth” to the apparatus microcomputer 409by LTC transmission.

This flow may include another routine for returning the F value to F=Fthwhen the F value becomes smaller than Fth due to any reason.

The process by the apparatus microcomputer 409 will be explained withreference to the flow chart of FIG. 5.

In step #10, the apparatus microcomputer 409 transmits a calculated ΔAvalue to the lens microcomputer 410 by CTL. If the apparatusmicrocomputer 409 determines in step #11 that it has received a signalmeaning that the aperture stop is opened, from the lens microcomputer410 by LTC, the apparatus microcomputer 409 advances to step #12 toconfirm underexposure again (not shown) and perform “up gain” (up CCDsensitivity).

If the apparatus microcomputer 409 has received in step #11 “F=Fth”meaning that the aperture stop unit 136 is not opened, the apparatusmicrocomputer 409 advances to step #13 to confirm overexposure again(not shown). If YES in step #13, the apparatus microcomputer 409 shiftsto step #14 to speed up the shutter speed of a shutter (not shown).

The operation in the auto mode has been described, and the sameoperation is also done in the portrait mode.

According to the third embodiment, the limit value of a small aperturein the aperture stop unit 136 is changed in accordance with informationconcerning the pixel pitch of a CCD used so as to prevent imagedegradation caused by small-aperture diffraction. Especially in a fullautomatic exposure adjustment mode called a portrait mode or auto mode,the aperture stop unit 136 is prevented from operating to an aperturevalue smaller than the limit value.

Accordingly, image degradation by the diffraction phenomenon can beprevented without excessively limiting the exposure adjustable range bythe aperture stop.

Fourth Embodiment

The third embodiment assumes a mode called a portrait mode or auto mode.The fourth embodiment of the present invention will exemplify a casewherein an F value of an aperture diameter smaller than F=Fth is set ina manual mode or the aperture stop unit operates to an F value of anaperture diameter smaller than F=Fth when correct exposure is to beobtained at a set shutter speed in a shutter priority mode.

In this case, a lens microcomputer 410 notifies an apparatusmicrocomputer 409 of an aperture diameter smaller than F=Fth by LTCtransmission. Then, an image pickup apparatus body 419 displays on adisplay (not shown) such as an electronic viewfinder or LCD viewfinder awarning message that image degradation occurs owing to small-aperturediffraction.

This warning may be issued to the user by lights-on or flashing of anLED lamp or sound in addition to display of the warning message.

In this fashion, any warning that image degradation occurs due todiffraction is issued when the aperture value or shutter speed ismanually set or when an aperture diameter smaller than a limit valuemust be used at a set shutter speed in the shutter speed priority mode.In accordance with this warning, the user attaches, e.g., an ND filterto avoid image degradation. In the aperture priority mode, imagedegradation can be avoided by inhibiting setting the F value to anaperture diameter smaller than a limit value. Image degradation may alsobe prevented by installing in a lens 418 an ND filter having a pluralityof transmission light quantity values or a filter capable of changingthe transmission light quantity, and automatically or manually insertingthe ND filter or filter in the optical axis in front of the CCD 1.

The above-described embodiments optimally control the exposure when aplurality of image pickup apparatus bodies with different CCD formsallow interchanging lenses and can use a common lens in an image pickupsystem such as a video camera or digital camera using an image pickupdevice such as a CCD. Even if a plurality of image pickup apparatusbodies with different pixel pitches of image pickup devices such as CCDsare prepared for a single lens, information concerning the image pickupdevice is transmitted to the lens side, and the lens side changes thelimit value of a small aperture on the basis of the information. Thus, asystem and lens free from any image degradation caused by small-aperturediffraction can be provided regardless of a combination of a lens and animage pickup apparatus body having any form of an image pickup device(or image pickup system apparatus and apparatus body).

The exposure control range by the aperture stop can be maximallyutilized without any image degradation caused by the diffractionphenomenon even if an optimal image pickup apparatus body (camera body)is selectively used for a single lens in accordance with the intendeduse such as high-sensitivity image pickup, high-resolution image pickup,or image pickup of a moving picture, or if an optimal image pickupsystem apparatus is mounted on an image pickup apparatus body inaccordance with high-sensitivity image pickup, high-resolution imagepickup, or image pickup of a moving picture.

When an aperture diameter smaller than a limit value must be used at anarbitrarily set shutter speed, a message of this effect is issued tocause the user to attach, e.g., an ND filter or to inhibit image pickup.This can also prevent image degradation.

As has been described above, the above embodiments can provide a lens orimage pickup system which prevents image degradation caused by thediffraction phenomenon without limiting the exposure adjustable range byan aperture stop even if an optimal image pickup apparatus body isselectively used for a single lens in accordance with the intended usesuch as high-sensitivity image pickup, high-resolution image pickup, orimage pickup of a moving picture.

The above embodiments can provide an image pickup system which preventsimage degradation caused by the diffraction phenomenon without limitingthe exposure adjustable range by an aperture even if an optimal imagepickup system apparatus is mounted on an apparatus body in accordancewith the intended use such as high-sensitivity image pickup,high-resolution image pickup, or image pickup of a moving picture.

The above embodiments can provide a lens or image pickup system capableof issuing a warning to avoid image degradation in advance when anaperture diameter smaller than a limit value must be used based oninformation concerning arbitrary set exposure control.

1. A lens apparatus interchangeably mountable on a plurality of imagepickup apparatuses in which forms of image pickup elements thereof aredifferent from others, the lens apparatus comprising: receiving meanswhich receives at least one of information relating to a pixel number ofthe image pickup element, a pixel pitch of the image pickup element, andan aperture value of an aperture stop member set in accordance with thepixel pitch, which are transmitted from the image pickup apparatus; andcontrol means which changes a set value Fth relating to a use limit of asmall aperture of the aperture stop member, on the basis of theinformation received by the receiving means, wherein when an aperturevalue F presently set in the image pickup apparatus becomes smaller thanthe set value Fth, the control means controls the aperture value F toreturn to the set value Fth.
 2. An image pickup system formed bycombining one of a plurality of image pickup apparatuses in which formsof image pickup elements thereof are different from others, and a lensapparatus interchangeably mountable on the one of the plurality of theimage pickup apparatuses, wherein each of the image pickup apparatusestransmits at least one of information relating to a pixel number of theimage pickup element, a pixel pitch of the image pickup element, and anaperture value of an aperture stop member set in accordance with thepixel pitch, which are transmitted from the image pickup apparatus,wherein the lens apparatus includes control means which changes a setvalue Fth relating to a use limit of a small aperture of the aperturestop member, on the basis of the information transmitted from the imagepickup apparatus, and wherein when an aperture value F presently set inthe image pickup apparatus becomes smaller than the set value Fth, thecontrol means controls the aperture value F to return to the set valueFth.